The following is a list of the best art known to the inventor at the time of the filing of this application:
2,729,885 to Wahl et al Jan. 10, 1956 PA1 3,135,048 to Daugherty et al June 2, 1964 PA1 3,137,068 to Quigley June 16, 1964 PA1 3,175,288 to Garwick et al Mar. 30, 1965 PA1 3,224,089 to Gibbons Dec. 21, 1965 PA1 3,457,642 to Steer et al July 29, 1969 PA1 3,606,058 to Davis Sept. 20, 1971
The patents to Wahl et al and Quigley both show simple spring loaded knife means mounted on the opposite sides of a conveyor means to slit the oppositely disposed parrallel walls of a carton or the like moving along the conveyor. The box is turned at 90.degree. while still on the conveyor and is between the knife stations, to complete the cutting of the remaining two sides of the carton.
Daugherty et al, Garwick et al and Gibbons each show a device adapted to cut only one side of a carton or box disposed at the work station. In using this kind of a set up, it is necessary to rotate the carton three times after cutting the first side of the box to complete the opening operation.
The Steer et al and Davis patents disclose conveyor arrangements disposed at right angles to each other for conveying a box or carton to be opened past cutting knives that are pressed against the opposite parrallel sides of the boxes.